- For rocks in which you can see crystals, you should, in general, use 'crystalline' not 'crystallized'. 'Crystallized rock' implies the rock as a whole crystallized - from a molten state or from a solution. In many cases, that will not be true. The crystals in many sedimentary rocks, for instance, arose from deposition of particles of other rocks (which happened to be crystalline) plus the deposition of mineral crystals in the pore spaces (from chemicals dissolved in pore fluids). On top of that, recrystallization may have occured, modifying the earlier crystals (that may occur in diagenesis or metamorphism).

- The environment where organisms lived can be different from the one where they became finally deposited (plant material is washed from deltas and can be deposited in a marine environment, eg.).

- Even a thin band of rocks can represent quite a large period of time, during which the environment can vary quite a lot (and it is complicated by hiatuses - periods not recorded in the rocks because of erosion or non-deposition). Even though a stratigraphic unit, such as the Coal Measures, may have a simple name, it may entail a range of lithologies and environments. For instance, although there may have been times when plants flourished on land/swamps, occassional submergence could easily allow the same area to see deposition of marine sediments and associated fossils. When you see an outcrop composed of different rock types, you are probably looking at manifestations of different environments.

In an area known for plant fossils, marine fossils may be uncommon. But they can occur, and can be be of special interest, resulting in papers being written about them. By way of an example, here are a couple concerning the Coal Measures.

'Marine horizons in the coal measures of south Wales'

Trueman, A. E., 1928

"Marine beds, some with abundant faunas, occur in the Anthra-comya pulchra zone at Cwmgorse, near Swansea, and in Yorkshire. Possible marine beds also occur at lower horizons in the former locality; they contain Orthoceras, Orbiculoidea, Lingula and other typically marine organisms."

'Lingula Horizons in the Coal Measures of Northumberland and Durham'

William Hopkins, University of Durham

Geological Magazine, Volume 71, Issue 04, April 1934, pp.183-189

"Previous to 1858, the Northumberland and Durham Coalfield was considered to be destitute of any fauna other than the usual non-marine type. In 1858, J. W. Kirkby gave the first indication of marine fossils in this coalfield. He obtained specimens of Lingula credneri (Geinitz) from shales some 17 feet above the Five-Quarter seam during the sinking of a shaft at Ryhope, 3 miles south of Sunderland (9). Some of these specimens are figured by T. Davidson (2)."

Your area, Ossett, has been under water. The BGS describes the Pennine Middle Coal Measures Formation as "swamps, estuaries and deltas. These rocks were formed in marginal coastal plains with lakes and swamps periodically inundated by the sea; or estuaries and deltas, and shallow seas". That is just the bedrock exposed at the surface. There are older rocks below and there were younger rocks above (since removed by erosion), some of which were probably also deposited in marine environments (although we know many were not).

It is a reasonable thought, thanks; especially as Syringopora is recorded from Yorkshire.

But I don't think it flies.

Dan's specimen has a fairly regular pattern of vertical and horizontal struts, whereas the structure in Syringopora is somewhat random horizontally; also in Dan's specimen the struts are narrow and probably solid, whereas in S. they are thicker (relative to the gaps between) and more tubular.

I've been trying to find an example of a plant with woody vascular bundles arranged in the right sort of structure, but without luck. (You may have noticed on old Antirrhinum (snapdragon) stems, there is a perforated woody inner part that remains for a while as old plants decompose; Broccoli and wallflower, likewise.)

By all means consider sending it to the NHM, but contact them first for advice (they may get a palaeontolgist to have a look at the discussion, which might give result in an ID).

Also, just because I and other viewers here don't recognize it, it doesn't mean it is a new species. I've been doing geology for over 40 years, and I still find plenty of stuff new to me but known to others.